Pitch-coking process and product



Patented Dec. 11, 1928.

outrun STATES PATENT OFFICE.

FREDERICK W. SPERR, JR., OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO THE KOIPPERS COMPANY, OF PITTSBURGH, IPENNSYLVANIA, A CORPORATION OF PENN- SYLVANIA.

PITCH-COKI'NG PROCESS AND PRODUCT.

No Drawing.

This invention relates to the PIOCBSS'IEOI coking pitch, such as is described in the pending application of Jose h Becker, for Letters Patent of the United tates, for pitch coking process and product, filed October 16,.

1919, Serial No. 330,988, and has for its object the production of coke from a primary mixture of pitch, bauxite or a substance of corresponding properties and ordinary coke breeze derived from the carbonization of coal, in a manner which substantially eliminates excessive intumescence and ebullition of the material-during the coking process.

In carrying out the invention, a mixture is formed of ordinary coke breeze derived from the carbonization of coal with a proportion of pitch, or other liquefiable bituminous material, and a proportion of bauxite, both the coke breeze and bauxite being infusible at coking temperatures so that foaming of the pitch in the coking process is checked and excessive intumescence and ebullition is eliminated. The finished coke is especially adapted for making electrodes for electric furnaces, especially as employed in the recovery-of aluminium from its ores and the employment of bauxite in the mixture to be coked, does not leave in the finished coke a residuum for eign to, nor introduce objectionable impurities into the material electrolytically treated in the electric furnace in which electrodes made of such coke are employed. The primary mixture thus formed, for example a mixture of pitch, bauxite and ordinary coke breeze derived from the carbonization of coal, may then be charged directly into a coke oven retort of ordinary typeand sub- I jected in the oven to the required coking heat. The coking process iscarried on eificiently, without the usual dificulties encountered in the coking of ordinary pitch, or other analogous liquefiable bituminous materials, which when subjected to thehigh temperatures necessary for coking, frequently boil and intumesce violently. This foaming and intumescing of pitch materials in coke ovens results in a mechanical loss of a large proportion of the coke and produces conditions in the oven or retort which seriously interfere with the closures and outlets of the oven or retort. The coke resulting from a mixture of pitch, bauxite and coke breeze for example, will be a highly homogeneous product,

and of great value in the manufacture of.

Application filed November 10,1919. Serial No. 337,013.

carbon electrodes, requiring coke which introduces no impurities into aluminium producing furnaces, inasmuch as the non-carbon residuum in such coke will be the same material, bauxite, that is electrolytically treated in such furnaces. In other words the residuum in theelectrodes will be homologous to the material treated in the furnaces. .It will be obvious to those skilled in the: art that in lieu of bauxite other substances having corresponding properties in similar situations may be employed- For instance, where the prod: not is to be used-in electric furnaces for the recovery of aluminum from its ores alumina or other ore containing the oxide of aluminum may be employed, as indicated in the Becker application above referred to, of which the present is an improvement. An advantageous application of the above stated discovery is as follows: A mixture of pitch, bauxite, and ordinary coke breeze is formed'by thoroughly mixing 40% pitch, 30% bauxite and 30% ordinary coke breeze. These ingredients may be mixed together in any preferred way; it will be found convenient however to first thoroughly mix together the pitch and the bauxite and then add the coke breeze to the mixture, repeating the mixinguntil all three ingredients are thoroughly mixed together. It will be found preferable to grind the pitch before mixing so that it will pass through a screen of relatively fine mesh, for example, a 1/4 inch screen. The coke breeze should also be in a relatively fine pulverulentcondition and it will be found convenient to screen the coke breeze through ascreen of 1/8 inch mesh, to insure uniformity. The relative proportions of the three ingredients constituting the mixture may obviously be varied, provided the mixture contains a sufiicient proportion of bauxite and ordinary coke breeze to prevent excessive intumescence and foaming, when subjected to the required coking heat. This mixture may then be charged into an oven and coked. C

The term pitch is used in the appended claims in a generic rather than a technically specific sense, and to include ebulliently liquefiable bituminous materials of the general nature of pitch; and my invention ineludes the treatinent of such materials to produceacoke which will introduce substantially no impurities into reactions in which it is intended to be employed and yet remedy the coking difficulties hereinabove indicated.

In the hereinabove identified co-pending application of Joseph Becker, there is set forth and claimed processes relating to making coke from a mixture of pitch or the like, with a material, or materials, of which the residuum, in the resultant coke, is homologous with a material to be treated in a metallurgical furnace, and no claim is made in the present application for subject matter claimed in the said application of Joseph Becker.

The processes of the invention may be practiced in various ways, other than the particular embodiment that has been described for purposes of illustration, and still be within the scope and subject matter of the claims hereinafter made.

I claim:

1. In a pitch coking process: forming a primary mixture of proportions of pitch, bauxite and coke breeze derived from the carbonization of coal and making coke directly from such primary mixture, by subjecting such mixture to coking heat; substantially as specified.

2. In a pitch coking process; forming a primary mixture of substantially 40% pitch, substantially 30% bauxite and substantially 30% coke breeze derived from the carbonization of coal and makingcoke directly from such primary mixture by subjecting such mixture to coking heat; substantially as specified.

3. As a new product, a coking mixture composed of pitch, bauxite and coke breeze clerived from the carbonization of coal, the pro: portion of bauxite and coke breeze employed being not greater than of the total mass.

at. As a new product, a coking mixture composed of substantially 40% pitch, substantially 30% bauxite and substantially 30% coke breeze derived from the carbonization of coal. 1

- 5. As a new product, coke manufactured from a primary mixture of pitch, bauxite, and

coke breeze derived from the carbonization of coal; substantially as specified.

6. As a new product, coke manufactured from a mixture of substantially 40% pitch,

substantially 30% bauxite, and substantially 30% coke breeze derived from the carbonization of coal; substantially as specified.

7. In a pitch coking process for the production of coke for employment in electrodes of electric furnaces; mixing pitch with coke breeze derived from the carbonization of coal and a proportion of a material foreign to said substances that is substantially infusible at cooking temperatures and whose residuum in the resultant coke is homologous with the material. to be treated in such furnaces; and subjecting the aforesaid mixture to coking heat; substantially as specified.

8. In a pitch coking process for the production of coke for employment in devices designed to be subjected to intense heat; mixing pitch with coke breeze derived from the carbonization of coal and a proportion of a material foreign to said substances that is substantially infusible at coking temperatures and Whose residuum in the resultant coke is homologous with the material to be treated in such devices; and directly making coke of such mixture; substantially as specified.

9. As a new product, for use in devices designed to be subjected to intense heat, coke manufactured from a mixture of pitch, coke breeze and a material foreign to said substances that is substantially infusible at coking temperatures and whose residuum in the resultant coke is homologous with the material to be treated in such devices, substantially as specified.

10. As a new product, coke manufactured from pitch, an oxide of aluminum and coke breeze, substantially as specified.

In testimony whereof I have hereunto set my hand.

FREDERICK W. SPERR, J R. 

